Where do clouds form?
Everybody knows that clouds form where the humidity reaches 100%. The rest needs some understanding of meteorology which I will largely skip over – partly because it isn’t my area of expertise and partly because I set out to produce an easy to digest collection of practical advice for pilots. The theory is anyway of little use without a website on which one can push buttons and actually get the data. The cloud bases are to some degree predictable from the convergence of the reported surface temperature and dew point and there is even a formula which has been known to occassionally work: temperature-DP spread multiplied by 400ft, so if the surface temperature is +10C and the DP is +4C you might expect the bases to be around 2400ft. This works with some cloud types better than others. Cloud base forecasts are widely available in TAFs and other aviation data. These tend to be reasonably accurate because they are normally produced by full-time weather professionals who have access to a wid
